142 The Sweet Potato 



by being nearly concealed under the heavy load of ex- 

 crement which it supports on its spine. Usually it is 

 of a dark brown color, being browner around the edges 

 and a lighter shade along the middle. The pupa re- 

 sembles the larva. 



The mottled tortoise beetle (Coptocycla signifera). 



This beetle is strikingly different from the other 

 species in being black marked with golden spots and 

 usually with a band of black extending across the 

 shoulders to the edge of the transparent margin of the 

 wing-covers. The larva is a pale smooth yellow during 

 its early stages, but after the last molt the color changes 

 to green, and after the excrement is removed from the 

 fork it is very difficult to recognize on a green leaf. 

 The larva does not feed during this last stage. The 

 pupa is also green, but probably brighter than the larva, 

 and marked by a few black bands around the first 

 abdominal spiracles. 



The argus tortoise beetle {Chelymorpha argus). 



This is the largest of the tortoise beetles, although 

 it is not as common as the preceding species. It is 

 also injurious to several other plants, among these being 

 raspberry, horse-radish and milkweed. The adults are 

 usually brick-red in color with six black dots on the pro- 

 thorax and six on each wing-cover which is variable in 

 size and color. The extension of the wing-covers 

 present in the other tortoise beetles is lacking in this 

 species. The eggs are laid in a bunch supported by a 

 long stalk. When the larva hatch, they remain close 

 together and very quickly defoliate the plant. When 



